Recent data suggest that there is interaction between peripheral angiotensin II and nitric oxide. However, sparse information is available on the mutual interaction of these two compounds in the brain. The potential intercourse of nitric oxide with brain neuropeptides needs to be substantiated by assessing its local production and gene expression of the synthesizing enzymes involved. The aim of the present study was to evaluate whether the gene expression of brain nitric oxide synthase (bNOS) is related to the sites of gene expression of different components of the rat brain renin angiotensin system (renin, angiotensin converting enzyme (ACE) or angiotensin receptors of AT1 and AT2 subtypes). The levels of corresponding mRNAs were measured and correlated in nine structures of adult rat brain (hippocampus, amygdala, septum, thalamus, hypothalamus, cortex, pons, medulla and cerebellum). As was expected, positive correlation was observed between renin and angiotensin-converting enzyme mRNAs. Moreover, a significant correlation was found between brain NO synthase and AT1 receptor mRNAs, but not with mRNA of the AT2 receptor, ACE and renin. Parallel distribution of mRNAs coding for bNOS and AT1 receptors in several rat brain structures suggests a possible interaction between brain angiotensin II and nitric oxide, which remains to be definitely demonstrated by other approaches., O. Križanová, A. Kiss, Ľ. Žáčiková, D. Ježová., and Obsahuje bibliografii
NO concentration in the femoral artery and femoral vein of anesthetized dogs was found to be 154.2± 5.6 nM and 90.0± 12 nM, respectively. Inhibition of NO synthase (NOS) slightly decreased the basal NO concentration in femoral artery from 154.2± 5.6 to 137.2± 3.3 nM. Acetylcholine-induced increase in NO concentration was slightly but still significantly attenuated, suggesting that very probably L-NAME did not inhibit all sources of nitric oxide (NO). Local NOS inhibition in the posterior hypothalamus dose-dependently increased systemic blood pressure (BP) in rats. Short-term general NOS inhibition in anesthetized dogs increased diastolic BP but not systolic BP. The heart rate after one-hour down-fluctuation returned to initial values. Proteosynthesis in the myocardium and both branches of the left coronary artery increased, but this was not supported by polyamines, since the activity of ornithine decarboxylase declined. Long-term general NOS inhibition elicited a sustained BP increase, a decrease in heart rate, cardiac hypertrophy and an increase in wall thickness of the coronary and carotid artery. The results indicate that NO deficiency itself plays a role in proteosynthesis and cardiac hypertrophy, in spite of relatively small increase in diastolic blood pressure and no change in systolic blood pressure, at least after an acute L-NAME administration. The hypotension response to acetylcholine and bradykinin studied in anesthetized NO-compromised rats, was unexpectedly enhanced. The elucidation of this paradoxical phenomenon will require further experiments., M. Gerová., and Obsahuje bibliografii
In this article the development of blue light emitting diodes (LEDs, awarded by the Nobel Prize for Physics in 2014) is described from the point of view of material science and technology. Further, both challenges and benefits from the use of gallium nitride for LEDs are discussed in the article., Josef Stejskal, Jindřich Leitner, Zdeněk Sofer., and Obsahuje seznam literatury
An experiment was conducted to monitor the effect of the length of environmental exposure of faeces on the content of nitrogen and diaminopimelic acid. We used samples of the droppings of wild red deer and examined them for the content of N and DAPA upon exposure to field conditions for 0–7 days during the growing season and for 0–30 days in winter, and after a year of storage in dried and frozen state. In relation to nitrogen level, there were no differences between the samples of fresh droppings and those after different lengths of exposure to ambient conditions before analysis and no differences between fresh and stored samples. As to DAPA level, there were no differences between the samples of fresh droppings and those after exposure. Nitrogen and DAPA levels in the droppings were stable and can be measured in both fresh samples and samples that have been exposed to ambient conditions for one week in summer or one month in winter.
Nitrogen defíciency caused pronounced reductions in the photosynthetic capacity and differential losses in chlorophyll, cytochrome / and Mg2'''>specific ATPase amounts or activities in suspension cultured cells of Chenopodium rubrum L. This reduced outfit of the photosynthetic machinery and limited protein tumover capacity are possible reasons for our observation that nitrogen deficiency exacerbates the hannful effects of high irradiance on photosystem 2 photochemical efficiency. The effect of nitrogen defíciency on photoinhibition increased over a broad range of photon flux densities and it was detectable in both the short-term and long-tenn experiments. Differences in the effects of the nitrogen regime and irradiance on several growth parameters were demonstrated. The main effect of nitrogen defíciency was a reduction of protein synthesis and cell division, whereas the irradiance chiefly affected the accumulation of carbon in the cell suspensions. Synergistic effects of nitrogen regime and irradiance could also be demonstrated for betalain accumulation which was the greatest under high irradiance and expressed nitrogen defíciency.
Miscanthus is one of the most promising bioenergy crops with high photosynthetic nitrogen-use efficiency (PNUE). It is unclear how nitrogen (N) influences the photosynthesis in Miscanthus. Among three Miscanthus genotypes, the net photosynthetic rate (PN) under the different light intensity and CO2 concentration was measured at three levels of N: 0, 100, and 200 kg ha-1. The concentrations of chlorophyll, soluble protein, phosphoenolpyruvate carboxylase (PEPC), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit, leaf anatomy and carbon isotope discrimination (Δ) in the leaf were analyzed to probe the response of photosynthesis in Miscanthus genotypes to N levels. PN in all genotypes rose significantly as N application increased. The initial slope of response curves of PN to Ci was promoted by N application in all genotypes. Both stomatal conductance and Ci were increased with increased N supply, indicating that stomatal factors played an important role in increasing PN. At a given Ci, PN in all genotypes was enhanced by N, implying that nonstomatal factors might also play an important role in increasing PN. Miscanthus markedly regulated N investment into PEPC rather than the Rubisco large subunit under higher N conditions. Bundle sheath leakiness of CO2 was constant at about 0.35 for all N levels. Therefore, N enhanced the photosynthesis of Miscanthus mainly by increasing stomatal conductance and PEPC concentration., X.-P. Feng ... [et al.]., and Obsahuje bibliografii
In a two-year experiment (2002-2003), five N application rates [0, 60, 120, 180, and 240 kg(N) ha-1, marked N0, N60, N120, N180, and N240, respectively] were applied to sugar beet cv. Rizor arranged in a Randomized Complete Block design with six replications. Leaf shape parameters [leaf area (LA), maximum length (L), maximum width (W), average radial (AR), elongation (EL), and shape factor (SF)] were determined using an image analysis system, and leaf area index (LAI) was non-destructively measured every two weeks, from early August till mid-September (four times). Years, samplings, and their interaction had significant effects on the determined parameters. Fertilization at the highest dose (N240) increased L and sampling×fertilization interaction had significant effects on LA, L, W, and SF. For this interaction, W was the best-correlated parameter with LA and LAI meaning that W is a good predictor of these parameters. Two proposed models for LA estimation were tested. The model based on both leaf dimensions [LA = 0.5083 (L×W) + 31.928] predicted LA better than that using only W (LA = 21.686 W - 112.88). Instrumentally measured LAI was highly correlated with predicted LAI values derived from a quadratic function [LAI = -0.00001 (LA)2 + 0.0327 LA - 2.0413]. Thus, both LA and LAI can be reliably predicted non-destructively by using easily applied functions based on leaf dimensions (L, W) and LA estimations, respectively. and J. T. Tsialtas, N. Maslaris.
Five cyanobacterial symbionts from Azolla filiculoides, two symbionts from Az. microphylla and two free-living cyanobacteria Nos toe muscorum and Anabaena variabilis were analyzed for chlorophyll (Chi) a, carotenoids and phycobiliprotein contents, heterocyst frequency and nitrogenase activity. The symbiont AS-S1 as well as the free-living N. muscorum and An. variabilis contained highest amounts of Chi a and lowest amounts of carotenoids. The C-phycocyanin content was always higher than that of allo-phycocyanin and C-phycoerythrin. Among the symbionts, AS-S1 contained the highest amount of C-phycocyanin and highest nitrogenase activity. Heterocysts were more abundant in An. azollae than in free-living cyanobacteria.